The present invention relates to the field of modular connectors and more particularly, to the field of multi-port jacks.
Data communication networks are being developed which enable the flow of information to ever greater numbers of users at ever higher transmission rates. However, data transmitted at high rates in multi-pair data communication cables have an increased susceptibility to crosstalk, which often adversely affects the processing of the transmitted data. The problem of crosstalk in information networks increases as the frequency of the transmitted signals increases.
In the case of local area network (LAN) systems employing electrically distinct twisted wire pairs, crosstalk occurs when signal energy inadvertently xe2x80x9ccrossesxe2x80x9d from one signal pair to another. The point at which the signal crosses or couples from one set of wires to another may be 1) within the connector or internal circuitry of the transmitting station, referred to as xe2x80x9cnear-endxe2x80x9d crosstalk, 2) within the connector or internal circuitry of the receiving station, referred to as xe2x80x9cfar-end crosstalkxe2x80x9d, or 3) within the interconnecting cable.
Near-end crosstalk (xe2x80x9cNEXTxe2x80x9d) is especially troublesome in the case of telecommunication connectors of the type specified in sub-part F of FCC part 68.500, commonly referred to as modular connectors. The EIA/TIA of ANSI has promulgated electrical specifications for near-end crosstalk isolation in network connectors to ensure that the connectors themselves do not compromise the overall performance of the unshielded twisted pair interconnect hardware typically used in LAN systems. The EIA/TIA Category 5 electrical specifications specify the minimum near-end crosstalk isolation for connectors used in 100 ohm unshielded twisted pair Ethernet type interconnects at speeds of up to 100 MHz.
While it is desirable to use modular connectors for data transmission for reasons of economy, convenience and standardization, such connectors generally comprise a plurality of electrical contacts and conductors that extend parallel and closely spaced to each other thereby creating the possibility of excessive near-end crosstalk at high frequencies.
In addition, as the size of electronic components has become reduced with advances in semiconductor technology, it has become increasingly necessary to increase the number of modular connector ports which can be mounted within a given area.
It is an object of the invention to provide new and improved modular jacks which operatively reduce near-end crosstalk.
It is another object of the invention to provide new and improved multi-level modular jacks which operatively reduces near-end crosstalk.
It is yet another object of the invention to provide new and improved multi-level jacks which enable the jacks to be placed one on top of another allowing easy insertion and removal of plugs into the jacks.
It is another object of the invention to provide new and improved jacks which include a dedicated vent passage to operatively allow for the passage of air through the jack.
It is still another object of the invention to provide new and improved jacks which define a recess receivable of a printed circuit board to thereby reduce the height extension of the jack above the circuit board to which it is mounted.
It is still another object of the invention to provide a new and improved insert for a jack.
It is still another object of the invention to provide a new and improved method for manufacturing inserts for a jack.
In order to achieve at least some of these objects, and others, in accordance with a first embodiment of the present invention, a bi-level offset multiple port jack is provided and includes an outer housing part having a top wall, a bottom wall and a front face having a mid-portion arranged substantially parallel to and between the top wall and the bottom wall, and inner housing parts. The front face of the outer housing part defines a first row of at least one aperture between the mid-portion and the top wall and a second row of at least one aperture between the mid-portion and the bottom wall. The aperture in the first row has a plane of symmetry offset in relation to a plane of symmetry of the aperture in the second row such that only a portion of the aperture in the first row is directly opposed to the aperture in the second row. The inner housing parts are arranged in the outer housing part to define plug-receiving receptacles with the outer housing part, each plug receiving receptacle is in alignment with a respective aperture in the front face of the outer housing part. Each inner housing part includes contact/terminal members for engaging contacts of a plug insertable into a respective one of the plug-receiving receptacles. Each of the plug-receiving receptacles has a top wall and a bottom wall and is configured to accept a modular type plug having a resilient latch. In accordance with this embodiment, the upper level plug receptacles are configured to receive a resilient latch of a modular type plug in their top wall, the lower level plug receptacles are configured to receive a resilient latch of a modular type plug in their bottom wall. With this configuration, if a second bi-level offset multiple port jack is mounted above or below a first bi-level offset multiple port jack, and modular plugs are inserted into the receptacles of the first and second jacks, the resilient latches of the plugs secured within the first jack will be offset with respect to the resilient latches of the plugs secured within the second (adjacent) jack, thereby allowing the first and second jacks to be mounted more closely together.
In accordance with a further embodiment of the bi-level offset multiple port jack in accordance with the invention, at least one vent is provided in the jack to allow air to flow from the face of the jack through to the components on a printed circuit board to which the jack is mounted. This configuration is particularly advantageous in applications in which the jack is mounted to a face plate of an enclosed housing.
The outer housing part may also include a forward bottom portion adjacent the front face, an upper back portion adjacent the top wall, a rearward bottom portion adjacent the upper back portion and a lower back portion extending between the forward and rearward bottom portions to thereby define a recess at a rear of the outer housing part extending between lateral walls. The recess is receivable of a printed circuit board. This provides an advantage of reducing the necessary height extension of a jack mounted on a PCB above the PCB.
In another embodiment of the invention, the contact/terminal members in each inner housing part include at least one pair of contact/terminal members operatively forming a wire pair which cross over one another. The contact/terminal members include a contact portion adapted to extend into the respective plug-receiving receptacle, a terminal portion adapted to be connected to a printed circuit board and an intermediate bridging portion extending between the contact portion and the terminal portion. The cross over of the contact/terminal members occurs in the intermediate portion. Also, a portion of the intermediate portion of one contact/terminal member of the crossover pair is situated in a first plane in the inner housing part and a portion the intermediate portion of the other contact/terminal member of the crossover pair is situated in a second plane different from the first plane to thereby enable cross over the contact/terminal members without contact therebetween. Preferably, the contact/terminal members cross over one another twice such that the relative position of the contact/terminal members at the terminal portion and at the contact portion is the same. In accordance with this embodiment, near-end cross talk between the conductor pair is reduced due to the crossover configuration. In addition, by providing a double crossover of the conductor pair, the modular jack can maintain the standard footprint of an RJ type jack, while providing reduced cross-talk in comparison to standard RJ-type jacks. Preferably, both of the crossovers of the conductor pair occur in the same plane. In accordance with a further embodiment of the invention, the double crossover configuration is incorporated into the bi-level offset multiple port jack described above to provide a compact, multiple port jack which exhibits reduced cross-talk.
In another embodiment of the invention, a metallic shield for enclosing the outer housing part and the inner housing parts is provided. The shield includes a panel having at least one cantilevered spring beam and at least one bifurcated grounding tab connected to each spring beam. The spring beam is substantially planar and each grounding tab includes a pair of fingers extending out of the plane of the spring beam and outward from the outer housing part. The shield may also include a panel including a PCB grounding post. The PCB grounding post includes a leg portion and a foot portion including mount sides terminating in at least one tine. The foot portion is adapted to be inserted into a mounting hole in a printed circuit board to which the jack is mounted such that upon insertion of the foot portion, the mount sides are compressed inwardly and press against sides of the mounting hole.